In my case, I knew what I wanted to solve and how to state the equations, simultaneous linear equations, rectangular and polar notation calculations, etc. and used it to resolve the equations. I also spent the time to learn to resolve rectangular and polar equations on my TI-83. It being somewhat handier than using the computer. I downloaded Maxima after Mr. Al told me about it but it has quite a learning curve and I haven't taken the time to learn it. It is more like programming than just putting the equation in the correct notation to resolve. I did spend a few hours working with it and reading some tutorials on it. The Wolfram is online and Mathematica resides on my computer as an offline application.

I always liked Casios and at one time used HP and reverse polish notation but was given the TI-30 solar and TI-83 after my kids were through using them in HS and college and still use them since they won't die as all my other calculators did. MS does have the MS Mathematics app which is similar to Maxima.

I had a TI58 for a long time until it finally died on me back in the 1990's. It had a red LED display with 0.2 inch high digits.
I then went to i think it was a TI84 but it was too limited so i got a TI85.
Some years later that died too, so i went to a TI89. I like the TI89 power but it only does lower case variables which is totally ridiculous.
Then maybe a year ago i picked up a used TI85 which was cool because i had one in the past and i had software i wrote for it including a circuit analysis program. I hardly use it but back in the 90's i used it every day for hours on end. I discovered many things with that calculator including how to reduce the number of constants for encoding/decoding a JPG image which depended on a lot of matrix operations. The drawback to that one is it does not do any symbolic calculations at all while the TI89 does.

However, some years later i downloaded a PC version of the TI89 which gives you a TI89 right on your PC screen complete with skin and all. You have to own a TI89 though to be able to download the TI89 op sys image file. But i also downloaded an advanced HP calculator complete with op sys image.

I also wrote software for a number of different calculators including symbolic calculators that solve differential equations. Most of that took a back seat though when i downloaded my first copy of Maxima. Now i use Maxima with some helper programs i wrote to do different things, as well as programs to calculate things that are hard to get to work on Maxima or other types of software. These programs are often dedicated to one specific task but some can do different things in a more general way. I also wrote a huge math library which i use with my programs to handle complex numbers and various other types of the usual calculations.

Back in college, I got an HP48G because I liked the RPN -- loved it then, love it now. Although a few years ago I thought I'd treat myself and get the latest, greatest upgrade in that product line. I still reach for my HP48G instead of that one.

But, I reach for WolframAlpha and Mathematica before I reach for the calculator.

Back in college, I got an HP48G because I liked the RPN -- loved it then, love it now. Although a few years ago I thought I'd treat myself and get the latest, greatest upgrade in that product line. I still reach for my HP48G instead of that one.

But, I reach for WolframAlpha and Mathematica before I reach for the calculator.

While TI owns the academic market, I am still an HP fan. I have several, including a 48G and a 48. The G sits on my desk because the 48 uses N cells and they aren't common. I also have an IR printer which I rarely use but it's so cool it sits out anyway.

My first HP was a 25, not even the C model. 49 steps of programming, no persistent memory.

While TI owns the academic market, I am still an HP fan. I have several, including a 48G and a 48. The G sits on my desk because the 48 uses N cells and they aren't common. I also have an IR printer which I rarely use but it's so cool it sits out anyway.

My first HP was a 25, not even the C model. 49 steps of programming, no persistent memory.

Oh yeah you reminded me of my first programmable calculator too, it was a Radio Shack and i think it had 50 steps of programming memory (har har). I loved it though and had a blast with it. Cant remember the year now, maybe mid 1970's or early 1970's.
RS was really thriving back then.

My first calculator was a TI 30, in 1976. In 1973, my father had a "miniature" four-banger that was about the size of two stacked packs of cigarettes and used a NiCd battery, very advanced. On top it had three pushbuttons for advanced functions: square root, square, and reciprocal.

Before that, it was slide rules. I had one, but I was a teenager and only used it lightly.